A mammalian expression vector(pSV_2,-EP) was reconstructed by inserting a oligonucleolide fragment into pSV_2dhfr plasmid.

• 对pSV_2dhfr质粒进行改造，切除dhfr基因，加入一个人工合成的寡聚核苷酸片段，构建成哺乳动物细胞表达载体(pSV_2-EP)。